A338439 a(n) = n! * [x^n] Product_{k=1..n, gcd(n,k) = 1} (1 + x^k/k).

1, 1, 0, 3, 8, 50, 144, 2394, 8448, 89424, 576000, 20124720, 57231360, 3213905760, 11285084160, 217204092000, 2843121254400, 187660890063360, 558255985459200, 64849189355274240, 239933887119360000, 8405611881201561600, 116110668405473280000, 13912098832249673932800

Offset: 0

Author

Ilya Gutkovskiy, Oct 27 2020

Keywords

• nonn

Crossrefs

Cf. A007838, A036998, A338437.

Programs

Mathematica

Table[n! SeriesCoefficient[Product[(1 + Boole[GCD[n, k] == 1] x^k/k), {k, 1, n}], {x, 0, n}], {n, 0, 23}]